As the raw input and output for this kind of application is analog, the AVR micro-controller is just the wrong tech to use. Dsp equipped processor chips would be a better match for this kind of application.

You can get a very impressive amount of noise reduction with just passive means. Much easier than dealing with DSP. I just use a pair of JVC HA-FX34s with the foam pieces replaced with ear plugs with a hole drilled in them.

An easy way is to just crank up the volume and use earplugs to get it back down to a comfortable level. It would almost certainly use less power than a DSP unless there's already one in your application. A cheap pair of earplugs would give 29dB of SNR improvement, probably more than you need.

As the raw input and output for this kind of application is analog, the AVR micro-controller is just the wrong tech to use. Dsp equipped processor chips would be a better match for this kind of application.

As the raw input and output for this kind of application is analog, the AVR micro-controller is just the wrong tech to use. Dsp equipped processor chips would be a better match for this kind of application.

where would i cheaply get one of these?

http://ww1.microchip.com/downloads/en/DeviceDoc/70324d.pdf

This brochure list 'noise cancellation' application information avalible, so search around their site.